UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE PEPERIKSAAN IJAZAH SARJANA MUDA SAINS DENGAN PENDIDIKAN EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE WITH EDUCATION SESI AKADEMIK 2013/2014 : SEMESTER 2 ACADEMIC SESSION 2013/2014 : SEMESTER 2 SCES1220 : KIMIA ORGANIK I ORGANIC CHEMISTRY I Jun 2014 June 2014 MASA : 2 jam TIME : 2 hours ARAHAN KEPADA CALON : INSTRUCTIONS TO CANDIDATES : Jawab SEMUA soalan. Answer ALL the questions. (Kertas ini mengandungi 4 soalan dalam 7 halaman yang dicetak) (This question paper consists of 4 questions on 7 printed pages)
1. (a) Lukiskan molekul yang berikut: Draw the following molecules: (i) 4-etil-3,4-dimetil-5-(1-metiletil)oktana 4-ethyl-3,4-dimethyl-5-(1-methylethyl)octane (ii) Konformasi kerusi yang paling stabil bagi 1,2,3,5- tetraklorosikloheksana The most stable chair conformer for 1,2,3,5-tetrachlorocyclohexane (iii) (iv) (3S,4Z)-5-bromo-3-kloro-4-heksen-1-una (3S,4Z)-5-bromo-3-chloro-4- hexen-1-yne 4,6,6-trimetilsiklookt-1-ena 4,6,6-trimethylcyclooct-1-ene Berikan nama IUPAC bagi sebatian di bawah: Provide the IUPAC name for the following compound: Dengan menggunakan formula unjuran Newman, lukis semua konformasi terpirau apabila sebatian di atas diputarkan (pada ikatan yang ditunjukkan di atas) serta nyatakan konformasi terpirau yang paling stabil. By using the Newman projection, draw all the staggered conformations when the compound above is rotated about the bond shown above, and state the most stable staggered conformation. (5 markah/marks) 2/7
(c) Konformer yang paling stabil bagi sebatian yang berikut ditunjukkan di bawah. Jelaskan permerhatian ini. The most stable conformer for the following compound is shown below. Explain this observation. (3 markah/marks) 2. (a) Antara carbanion di atas, yang manakah paling stabil. Jelaskan jawapan anda. Which of the above carbanions is the most stable. Explain your answer. (8 markah/marks) Berikan reagen atau produk(a F)untuk transformasi berikut: Give reagents or products (A F) for the following transformations: 3/7
(c)(i) Jawab soalan di bawah, berdasarkan molekul yang berikut. Answer the questions below, based on the following molecule: - Bulat dan namakan kumpulan berfungsi yang ada pada molekul di atas. Circle and name the functional groups present in the molecule above. - Kenalpasti kesemua pusat stereogenik (tandakannya dengan *), dan berikan konfigurasi (RatauS) bagimana-mana DUA pusat stereogenik bagi molekul berkenaan. Identify all the stereogenic centers (mark it with an *), and assign the configuration (R or S) of any TWO stereogenic centers in the molecule. (ii) Jawab soalan di bawah, berdasarkan molekul yang berikut. Answer the following questions, based on the following molecule (10 markah/marks) - Lukiskan unjuran Fisher bagi molekul di atas. Draw the Fischer projection for the molecule shown above. - Berikan konfigurasi bagi setiap pusat stereogenik Assign the configuration at each stereogenic center. 4/7
- Apakah hubungan diantara molekul yang ditunjukkan di atas dan molekul yang ditunjukkan di bawah. What is the relationship between the molecule shown above and the molecule shown below. 3. (a) Nyatakan bahan pemula, reagen dan hasil dalam tindak balas di bawah. Indicate the starting materials, reagents and products for the reactions below. (i) 1. BH 3 /THF 2. H 2 O 2 /HO - G (ii) 1. O 3, CH 2 Cl 2, -78 o C 2. Zn/H 2 O H HBr I (iii) (iv) + J K Br (v) OH (5 markah/marks) 5/7
Lukiskan kesemua jangkaan hasil termasuk enantiomer dengan aturan (R,S) untuk tindak balas berikut. Draw all products including enantiomers with (R,S) designation for the reactions below. (8 markah/marks) (c) Pendehidratan bermangkin asid bagi 2-metil-1-butanol dan 3-metil-1- butanol memberikan 2-metil-2-butena sebagai hasil utama. Cadangkan mekanisma untuk menerangkan keputusan ini. The acid-catalyzed dehydration of 2-methyl-1-butanol and 3-methyl-1- butanol gives the 2-methyl-2-butene as the major product. Suggest mechanisms that explain these results. (16 markah/marks) (d) Furan dan maleimida melalui tindak balas Diels-Alder pada 25 o C menghasilkan produk major endo. Apabila suhu tindak balas dinaikkan kepada 90 o C, hasil ekso menjadi produk major. Lukiskan kedua-dua bentuk hasil dan jelaskan tindak balas berkenaan. Furan and maleimide undergo a Diels-Alder reaction at 25 o C to produce the endo adduct as the major product. When the reaction is carried at 90 o C, the major product is the exo isomer. Draw the endo and exo adducts and explain the diffirent reaction outputs. (7 markah/marks) 6/7
4. (a) Berikan hasil-hasil (P S) daripada tindak balas di bawah. Give the products (P S) for the reactions below. (i) (ii) (iii) (4 markah/marks) Ion merkuri memangkin tindak balas di bawah. Cadangkan mekanisme tindak balas tersebut. The mercuric ion catalyzes the reaction below. Suggest the mechanism of the reaction. (10 markah/marks) (c) Lukiskan mekanisma dengan terperinci tindak balas berikut termasuk struktur sumbangan resonan dan resonan hibrid untuk ion perantaraan arenium. Draw the detailed mechanism for the following reaction including the respective contributing resonance structures and resonance hybrid for the arenium ion intermediates. TAMAT END 7/7